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Home My WebLink About2019/01/22 - Item #6 - Written Communications - Moot - 1-22-19 23129 Tiger Run Court, Suite 202 Carlsbad, CA 92010 619-609-0712 January 21, 2019 Raed Bisharat R. T. Bish, Inc. 501 Telegraph Canyon Road Chula Vista, CA 91910 Re: Chula Vista Wash ‘N Go Noise Analysis Review Mr. Bisharat: At your request, dBF Associates, Inc. has reviewed the noise analysis of the proposed Chula Vista Wash ‘N Go at 495 Telegraph Canyon Road in Chula Vista, California. The most recent noise analysis of the subject project is understood to be documented within the Noise Analysis Report (NAR) prepared by HMMH dated August 7, 2017. The following items were noted during the review. 1. The HMMH NAR states, in paragraph 4 on page 9: “Each of the nine dryers were determined to be in use at most 67% of the time, using a 2 car maximum tunnel capacity, 20 second drying time, and one minute total carwash time.” The proposed 80-foot-long car wash tunnel can process one vehicle in three minutes, and the typical distance between vehicles is 5 feet or less [Bisharat 2019]. Assuming a standard vehicle length of 15 feet, vehicles would be less than 10 seconds apart when the car wash is operating at full capacity. Under these conditions, to maximize efficient electricity and equipment use, it is likely that the dryers would be continuously operational rather than cycled off and on. I observed the blower cycle at the Wash ‘N Go Express car wash at 7959 Balboa Avenue in Kearny Mesa on Monday, January 21, 2019. This facility is an automated car wash similar to the proposed project. During the observations, the entrance queue ranged from one to four vehicles. Vehicles were observed exiting the tunnel as fast as every 30 seconds. 13 blowers were installed in the facility. The blowers were observed to be manufactured by Sonny’s The CarWash Factory. All of the blowers remained on, at full speed, when the time between vehicle exits was less than one minute. Over a 20-minute observation period, the fans were observed to turn off once, for less than two minutes. Each blower included a damper, which occasionally closed between vehicles; however, no noise level difference was observed. When at full capacity, the blowers would never turn off. Written Communications - Moot Item #6 Received 1/22/2019 Mr. Raed Bisharat January 21, 2019 Page 2 I observed the blower cycle at the Soapy Joe’s car wash at 740 San Marcos Boulevard on Friday, January 18, 2019. This facility is an automated car wash, similar to the proposed project. During the observations, the entrance queue ranged from three to seven vehicles. Vehicles were observed exiting the tunnel as fast as one per minute. The spacing between vehicles varied; the distance was typically one-half or one full car length, but entrance delays occasionally caused wider gaps. All of the blowers remained on, at full speed, during gaps of one car length or less. When at full capacity, the blowers would never turn off. As such, the operational assumption of 67% described in paragraph 4 on page 9 of the HMMH NAR is not accurate. If the model is revised to remove this incorrect assumption, the noise levels would increase by roughly 1.7 dBA, and would exceed the noise limits. 2. Project noise levels were not evaluated at the ARCO filling station across Halecrest Drive to the east, at 501 Telegraph Canyon Road. The filling station property is a commercial land use zoned CCD (Central Commercial Design District). The daytime (7:00 a.m. to 10:00 p.m.) noise limit at the west ARCO property line is 65 dBA Leq unless a higher ambient noise level is documented. The west ARCO property line is approximately 65 feet from the east project property line, and the project car wash exit would be approximately 25 feet west of its east property line. Using standard sound level propagation (6 dBA per doubling of distance), one dryer producing 86 dBA at 5 feet corresponds to approximately 60.9 dBA at 90 feet. Using logarithmic addition, nine dryers producing 60.9 dBA combine to produce approximately 70.4 dBA at the west ARCO property line. This exceeds the allowable level of 65 dBA Leq at this location. Similarly, project (and ambient) noise levels were not evaluated at the Chase Bank at 503 Telegraph Canyon Road or single-family residential properties along Douglas Street and beyond. 3. The HMMH NAR does not describe the noise modeling technique used to model the tunnel geometry. The appendix shows that the tunnel roof was modeled using a “floating screen,” but the north tunnel wall does not appear to have been modeled. The material and sound transmission characteristics of the tunnel are not discussed; certain materials can allow noise to permeate. A noise contour graphic would be effective to illustrate modeling techniques and results. Written Communications - Moot Item #6 Received 1/22/2019 Mr. Raed Bisharat January 21, 2019 Page 3 The Chula Vista Wash ‘N Go Noise Analysis Report prepared by HMMH dated August 7, 2017 is incomplete, is based on incorrect assumptions, and should be considered invalid in its current form. Please contact me at 619-609-0712 ×101 if you have any questions. Sincerely, dBF ASSOCIATES, INC. Steven Fiedler, INCE Principal References Bisharat, Raed. 2019. Conversation with Brad Sorenson at Sonny’s The CarWash Factory. January 17. Written Communications - Moot Item #6 Received 1/22/2019